This invention relates to an improvement in the process for producing glass beads described in U.S. Pat. No. 3,843,340 to Eugene J. Cone, entitled "Method and Apparatus for Producing Glass Beads", the disclosure of which is hereby incorporated by reference. In that process, beads of a predetermined size are formed by melting glass to a low viscosity and forcing it through an orifice to form a jet which breaks apart into beads. The process is particularly useful for making glass beads which are subsequently phase separated and leached to form the microporous catalyst supports disclosed in U.S. Pat. application Ser. No. 311,191, filed Dec. 1, 1972, by J. J. Hammel et al., now U.S. Pat. No. 3,843,341.
It has been found desirable to produce glass beads in various sizes for different end uses, but the bead forming process as taught in U.S. Pat. No. 3,843,340 would require that the orifice nozzle be removed and rebuilt in order to change bead sizes, a cumbersome and disruptive process. Furthermore, attempting to make larger beads by merely increasing the orifice diameter can lead to undesirable consequences because enlarging the orifice not only increases the thickness and velocity of the glass jet, but also would require a higher pressure to obtain a controlled jetting action. As a result, the total glass throughput is greatly increased, thereby necessitating a larger melter in order to assure adequate residence time for thorough melting. And when a fluid bath is being used to catch and cool the beads, an increased throughput can cause the fluid being used to become overheated. Thus it would be highly desirable to be able to change bead sizes quickly and easily, without unduly interrupting production, and without entailing a major redesign of the process equipment.